I think its like you divide 64 by 4. This will tell you how many sets of the 4 yards you have which is important to know since each 4 yards equals 7 inches. 64 divided by 4 is 16. Then multiple 16 by 7 since there's 16 sets of 4 and each set is 7 inches. This will come to a total of 112 inches.
I hope this helps, sorry if its wrong I haven't done this in a while, but I'm pretty sure its correct
